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<html lang="en">
<head>
    <meta charset="UTF-8">
    <meta http-equiv="X-UA-Compatible" content="IE=edge">
    <meta name="viewport" content="width=device-width, initial-scale=1.0">
    <title>Document</title>
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<body>
  <p>This page turns violet when you hold the V key.</p>
  <script>
    window.addEventListener("keydown", event => {
      if (event.key == "v") {
        document.body.style.background = "violet";
      }
    });
    window.addEventListener("keyup", event => {
      if (event.key == "v") {
        document.body.style.background = "";
      }
    });
  </script>


</body>
</html>